Entry and delivery guides for cold rolling mills

ABSTRACT

A steel mill, particularly a single strand reversing or tandem cold strip reduction mill is provided with an entry guide having a number of strip guide rolls mounted on a carriage or sledge, for displacement in the feeding direction as a complete assembly towards and away from the working rolls to facilitate rapid roll changing, particularly of the working rolls. The location of many components below the mill pass-line greatly improves operator viewability. In addition, a coolant hood cushions the upper working roll and back-up roll to permit the controlled application of coolant to the rolls without depositing or splashing significant quantities of coolant on strip passing through the mill. The hood and associated coolant supply system also facilitates thermal crowning of the top working roll and visual accessibility of the strip in the mill.

United States Patent [191 Field et al.

[111 3,913,369 [451 Oct. 21, 1975 [54] ENTRY AND DELIVERY GUIDES FOR COLD ROLLING MILLS [75] Inventors: Michael Frank Field, Sydney;

Charles James Cavell, Lachine, both 21 Appl. No.: 493,194

[30] Foreign Application Priority Data 24 I p A 22* 3,204,441 9/1965 Lyle 72/231 3,461,707 8/1969 Maltby.... 72/250 3,614,881 10/1971 Petros 72/250 3,828,599 8/1974 Withrow 72/163 Primary ExaminerMilton S Mehr Attorney, Agent, or FirmDaniel Patch; Henry C. Westin [5 7 ABSTRACT A steel mill, particularly a single strand reversing or tandem cold strip reduction mill is provided with an entry guide having a number of strip guide rolls mounted on a carriage or sledge, for displacement in the feeding direction as a complete assembly towards and away from the working rolls to facilitate rapid roll changing, particularly of the working rolls. The location of many components below the mill pass-line greatly improves operator viewability. In addition, a coolant hood cushions the upper working roll and back-up roll to permit the controlled application of coolant to the rolls without depositing or splashing significant quantities of coolant on strip passing through the mill. The hood and associated coolant supply system also facilitates thermal crowning of the top working roll and visual accessibility of the strip in the mill.

3 Claims, 4 Drawing Figures Sheet 2 of4 US. Patent 06:. 21, 1975 US. Patent Oct. 21,1975 Sheet 3 of4 3,913,369

ENTRY AND DELIVERY GUIDES FOR COLD ROLLING MILLS This invention is directed to a strip rolling mill having a strip guide arrangement and a coolant enclosure for controlling the administration of coolant to a roll or rolls of the mill.

In the operation of strip rolling mills, particularly in the case of cold strip mills, the duty of the working rolls is of such an arduous nature that it is sometimes necessary to change the working rolls every few hours. The strip guides, both at the oncoming and the off-going or delivery side of the mill are quite complex in their arrangement, in comprising a large number of components in closely spaced relation and require to be removed from the vicinity of the working rolls, to facilitate a required roll change. Furthermore, many previous arrangements provided a cluttered and visually impeded path for the strip through the mill. The present invention provides a guide arrangement mounted for retraction as a single entity on a carriage or sled and suitable for use on either the oncoming or off-going side of a mill.

The provision of coolant liquid to the back-up rolls and the working rolls of the mill is complex, owing to the need to minimize splashing of the coolant on to the strip, which otherwise produces streaking of the product, and also creates considerable mess in the vicinity of the stand, owing to the linear speed'attained by the strip on passage through the mill.

The provision of an upper roll enclosure or hood permits close control of coolant supply to permit thermal control of crown in the top working roll.

In operation, once a strip has been threaded through the mill, by appropriate use of the guides and reduction in thickness of the strip by the working rolls is commenced by the completion of one or more passes, it is usual to withdraw at least some of the upper guide rolls from contact with thestrip on its forward and revised passage through the mill.

Accordingly, the guide assembly of the present invention includes provision for variably positioning at least some of the rolls, primarily in relation to the mill pass-line.

The present invention thus provides, in a rolling mill having a pair of working rolls with a nip therebetween defining a workpiece pass-line for the passage of strip in reducing relation therethrough, a guide assembly having a plurality of pairs of guide rolls arranged in mutually opposed relation relative to the pass-line, means for adjusting the relative spacings between related ones of the rolls, and sled means carrying the assembly for displacement from a working position adjacent the working rolls to a displaced position away from the working rolls in the direction of the pass-line, to facilitate replacement'of the working rolls.

The invention further provides sled raising means for aligning lower ones of the guiderolls with the pass-line of the mill. There is further provided strip centering means mounted on the sled for spacing side guide rolls to bring astrip entering the mill into centered relation ;with the working rolls.

of a portion of a mill embodying an entry guide according to the present invention, and also showing details of a protective coolant enclosing hood in relation to the working and back-up rolls;

FIG. 2 is a general view showing portions of the guide system and the hood system in relation to changing of the working rolls;

FIG. 3 is a section at 3-3 of FIG. 1; and

FIG. 4 is a section at 4-4 of FIG. 1.

Referring first to FIGS. 1 and 2, the working rolls 6,6 and back-up rolls 8,8 of a reduction mill stand are shown, having the illustrated entry guide assembly 10 mounted on sled 12 for displacement along a supporting frame 14, away from the nip formed by the working rolls 6,6.

The guide supporting frame 14 is provided with position adjustment means comprising adjustable wedge blocks such as the wedge-block support 18 driven by shaft 20, which provides vertical adjustment of the frame relative to the mill passline P-P, whereby the level of the sled l2 and the components supported thereon may be adjusted in relation to the desired level of the pass-line P-P. I

Referring also to the other figures of the drawings, it will be seen that the entry guide 10 includes a series of closely spaced horizontal rolls, including a deflection mill 32 at the oncoming side having a pinch roll 24 mounted thereover, with an actuator 26 at each end thereof connected by a piston rod 28 to the pinch roll 24 for displacing the pinch roll to its normal, upwardly retracted position. The other horizontal rolls include a series of three bottom guide rolls 32, 34, 36 and related top rolls, respectively rolls 33, 35 and 37. A straightener and tensioning combination 38 or bridle comprise a pair of upper rolls 40, 42 and an adjustable lower roll 44, the nip forming relation of which is controlled by vertical displacement of the roll 44 under the action of the actuator 46 connected thereto by piston rod 48, a bell crank 50 and link 52. This bridle tensioning arrangement permits feeding of the strip with partial straightening, under controlled tension so that, although it may not be flat, the degree of working of the strip material in passing through the working rolls 6,6 will lie below the 'yield point of the material. Furthermore, the rolls of the bridle facilitate entry of the working piece into the nip of the rolls 6,6. As stated, it is usual on the first pass to maintain the horizontal rolls in sheet pressing relation, to ensure reasonable flatness and avoid edge buckling.

Movement of the sled 12 upon the supporting frame 14 is provided by an actuator 56 suspended by a pair of brackets 58 from the sled l2, and connected by piston rod 60 to a bracket and beam assembly 62 secured to the main frame 7 of the mill.

Referring to FIG. 3, the upward vertical displacement of the top horizontal guide rolls 33, 35 and 37 away from the pass-line is provided by a frame connected by yoke 71 to an actuator 72. The actuator 72 is suspended by a pair of brackets 74 from the sled l2 and is used to simultaneously raise up the top horizon- Referring more particularly to FIGS. 1 and 4, the sled 12 carries a series of vertically extending side guide rolls 90, 92, 94, 96, 98, 100 supported by brackets such as bracket 122 attached to the sled 12.

Each of the vertical side guide. rolls, such as roll 98 illustrated in FIG. 4, is mounted by way of bearings 106 carried by a drop-in spindle 108 mounted in the bracket 122. The side guide rolls are arranged in pairs, in the cross-machine sense, at opposite edges of the strip (shown in phantom), each pair being connected by means ofa centering mechanism 110. The centering mechanism 110 has a centrally located drive sprocket 112 mounted on shaft 114. On each end of the shaft 114 is located a threaded portion 116 on which a nut 118 is carried, only one half of the arrangement being illustrated. The handing of the threaded shaft portions 116 are respectively right and left handed, so that rotation of the sprocket 112 in a first direction will cause the nuts 118 to travel towards each other, and opposite rotation of the sprocket 112 will cause the nuts 118 to travel outwardly, away from each other.

Each of the nuts 118 is straddled by a frame 120 connecting with the bracket 122 and having a thrust plate 124 at the inner end thereof. Motion of the respective nut-118 carries the related bracket 122 with the nut. This motion in turn displaces the respective side guide roll in the desired direction. As the brackets 122 are spaced equally on opposite sides of the desired strip centerline, gradual closing of the paired vertical guide rolls towards each other by inching rotation of the sprocket 112 produces engagement between one or other of the rolls and the side of the strip and causes the work piece or strip to be pushed over by the respective contacting. vertical guide rolls to a central position, which is reached when both. of the rolls of a pair of guide rolls nip the workpiece therebetween..This centering action is completed before the strip enters the nip or bite of the working rolls 6,6. The innermost position of the illustrated guide roll 98 is shown in phantom in FIG. 4.- It will be evident that strip centering is achieved, regardless of initial strip width, within the limits of the range of stock size accommodated by the machine.

Referring to FIGS. 1 and 2 for particulars of the coolant spray and protective hood arrangement, a spray header 154 and nozzles 156 provide a controllable spray to the zone beneath the strip pass-line particularly for the bottom work roll 6. The upper work roll 6, and the upper back-up roll 8 are enclosed within a hood 150, the top of which has been omitted for purposes of clarity, with only the hood portion on the mill entry side being shown, together with a portion of a seal at the off-going side.

The hood 150, portions of which may be supported from the sled 12, has a lower wall portion 152 within which a plurality of coolant headers such as the single coolant header 154 illustrated are located. The inclined outer surface of the portion 152 also serves as a supplementary strip guide or cobble guard. The use of swivel connections and/or flexible hoses for the header coolant connections allows limited free movement of the coolant system without disconnection of the lines, to facilitate roll servicing and changing.

A plurality of spray heads 156 having flow control means (not shown) for the respective headers 154 permits controlled variation of flow rates of coolant across the width of the faces of the working and back-up rolls,

in the form of thermal profiling,'particularly useful for heat crowning the top work roll.

The edge of the wall 152, adjacent the top working roll 6 is formed by a seal 158, illustrated as being of the wiper type, although the use of dynamic gap seals also is contemplated. Drainage is provided from the hood at the back of the machine to direct the coolant flow below the strip.

K The provision of adjustable spring loaded stops 160 for positioning the hood towards the working rolls permits ready adjustment to the hood from outside the mill to control the horizontal load applied against the hood wall 152, which is balanced by the reactive load between the seal 158 and the contacting surface of upper working roll 6.

Referring to FIG. 2 a portion 152 of the hood and the hood edge seal 158 and the guide, including the apron 88 are shown in solid lines in the withdrawn position. Also in phantom, portions of these components are shown in an operative position, with the apron 88 located immediately adjacent the nip of the rolls 6,6. The direction of withdrawal of the rolls 6,6 to the front of the machine for roll changing purposes is indicated by the respective arrows.

A centrally located hood door 162 (FIG. 1) gives rapid access to the hood 150, particularly for the purpose of observing or adjusting the flow in the various coolant supply headers, when profiling the temperature control across the face width of the top working and back-up roll. An actuator (not shown), the piston 164 which is connected to the door hinge bracket 166, provides rapid and convenient actuation of the door 162, for expediting removal for roll change, and for back-up mill inspection and repair.

The range of adjustment provided by the stop 160 permits the hood to be adjusted towards the rolls to provide compensation for a full range of variation in size of both the working rolls 6 and back-up rolls 8, to maintain effective coolant sealing by the hood seals under all normal operating conditions.

It will be understood that the unitary delivery guide according to the present invention provided at the offgoing side of the mill does not require the provision of vertical side guide rolls.

In operation, owing to the use of the hood 150, and the location of the guide control components below the level of the pass-line, the operator of the stand is provided with a substantially unimpeded view of the top surface of the strip, which greatly facilitates the operation of the stand. Furthermore, the virtual exclusion of coolant flow quantities from the top face of the strip tends to preclude surface staining. While not illustrated, it will be understood that usual types of coolant damming rolls located inwardly of the bridle 38, between the bridle 38 and the working nip, .will be mounted on the sled 12 as a portion of the retractable unitary guide assembly. These damming rolls serve the usual function of restraining outward flow of coolant from the work zone.

The unitary retractable strip guides, according to the present invention, in addition to providing strip guidance in close proximity to the bite or nip of the working rolls 6, also provide substantially instantaneous retraction of the guides away from the working and back-up rolls, for facilitating roll changing, which aspect is further enhanced by the simplified coolant supply and coolant control system contained within the hood 150.

In accordance with the provisions of the patent statutes, we have explained the principle and operation of our invention and have illustrated and described what we consider to represent the best embodiment thereof.

We claim:

1. A unitary guide assembly in combination with a strip rolling mill which has a pair of working rolls and a pair of back-up rolls:

a plurality of pairs of guide rolls rotatably mounted in mutually opposed relation to guide a strip therebetween on passage of the strip along a pass-line through said working rolls of said mill,

guide support means supporting said assembly in spaced relation from said working rolls,

guide displacement means for moving said assembly from a working position adjacent said working rolls to a withdrawn position away from said working rolls in the direction of said pass-line to facilitate replacement of said working rolls,

a coolant enclosure substantially enclosing the upper of said back-up roll and a portion of the upper one of said working roll, and

seal means in said enclosure to substantially preclude, in operation, the downward passage of significant quantities of said coolant onto said strip passing therebeneath.

2. A unitary guide assembly in combination with a strip rolling mill which has a pair of working rolls and a pair of back-up rolls:

a plurality of pairs of guide rolls rotatably mounted in mutually opposed relation to guide a strip therebetween on passage of the strip along a pass-line through said working rolls of said mill,

guide support means supporting said assembly in spaced relation from said working rolls and located below said pass-line to provide good visibility of top ones of said guide rolls and of said strip,

guide displacement means for moving said assembly from a working position adjacent said working rolls to a withdrawn position away from said working rolls in the direction of said pass-line to facilitate replacement of the working rolls, and located below said pass-line to provide good visibility of top ones of said guide rolls and of said strip,

a coolant enclosure having seal means cooperating with the upper one of said working rolls to prevent downward passage of significant quantities of coolant onto said strip passing therebeneath,

coolant supply means to cool said rolls, and means for selectively controlling the quantity of coolant in a cross machine direction including flexible coolant connections to permit substantially unobstructed adjustment of the position of said enclosure relative to said working rolls.

3. A unitary guide assembly as claimed in claim 2, wherein said assembly is mounted on a sled and wherein said guide rolls include upper and lower horizontal rollers mounted in sets to apply flattening force to said strip prior to entry into said mill, including actuator means carried by said sled to provide relative vertical displacement between selected ones of said upper and lower rollers. 

1. A unitary guide assembly in combination with a strip rolling mill which has a pair of working rolls and a pair of back-up rolls: a plurality of pairs of guide rolls rotatably mounted in mutually opposed relation to guide a strip therebetween on passage of the strip along a pass-line through said working rolls of said mill, guide support means supporting said assembly in spaced relation from said working rolls, guidE displacement means for moving said assembly from a working position adjacent said working rolls to a withdrawn position away from said working rolls in the direction of said pass-line to facilitate replacement of said working rolls, a coolant enclosure substantially enclosing the upper of said back-up roll and a portion of the upper one of said working roll, and seal means in said enclosure to substantially preclude, in operation, the downward passage of significant quantities of said coolant onto said strip passing therebeneath.
 2. A unitary guide assembly in combination with a strip rolling mill which has a pair of working rolls and a pair of back-up rolls: a plurality of pairs of guide rolls rotatably mounted in mutually opposed relation to guide a strip therebetween on passage of the strip along a pass-line through said working rolls of said mill, guide support means supporting said assembly in spaced relation from said working rolls and located below said pass-line to provide good visibility of top ones of said guide rolls and of said strip, guide displacement means for moving said assembly from a working position adjacent said working rolls to a withdrawn position away from said working rolls in the direction of said pass-line to facilitate replacement of the working rolls, and located below said pass-line to provide good visibility of top ones of said guide rolls and of said strip, a coolant enclosure having seal means cooperating with the upper one of said working rolls to prevent downward passage of significant quantities of coolant onto said strip passing therebeneath, coolant supply means to cool said rolls, and means for selectively controlling the quantity of coolant in a cross machine direction including flexible coolant connections to permit substantially unobstructed adjustment of the position of said enclosure relative to said working rolls.
 3. A unitary guide assembly as claimed in claim 2, wherein said assembly is mounted on a sled and wherein said guide rolls include upper and lower horizontal rollers mounted in sets to apply flattening force to said strip prior to entry into said mill, including actuator means carried by said sled to provide relative vertical displacement between selected ones of said upper and lower rollers. 